1. Field of the Invention
The present invention generally relates to a semiconductor substrate suitable for improving a gettering characteristic, a semiconductor chip having the same, and a stacked semiconductor package having the semiconductor chip.
2. Description of the Related Art
In the semiconductor industry, packaging technologies for integrated circuits have continuously been developed to satisfy the demand toward miniaturization and mounting reliability. Recently, as miniaturization and high performance are demanded in electric and electronic appliances, various stacking techniques have been developed.
The term “stack” that is referred to in the semiconductor industry means to vertically pile at least two semiconductor chips or semiconductor packages. In the case of a memory device, by using a stacking technology, it is possible to realize a product having memory capacity at least two times greater than that obtainable through semiconductor integration processes. Since stacked semiconductor packages have advantages in terms of not only memory capacity but also mounting density and mounting area utilization efficiency, research and development for stacked semiconductor packages have been accelerated.
As an example of a stacked semiconductor package, a structure has been proposed, in which through electrodes are formed in semiconductor chips so that upper and lower semiconductor chips are physically and electrically connected with one another by the through electrodes.
However, a substance used as the through electrodes, for example, copper, is likely to diffuse to a semiconductor chip to cause a crystal defect. As a consequence, leakage current may be induced in the semiconductor chip, and the threshold voltage of a transistor is likely to be shifted, by which a refresh characteristic may deteriorate.
In order to cope with this problem, a method has been disclosed, in which the thickness of a dielectric layer (SiO2) formed between a through electrode and a semiconductor chip is increased so that copper diffusing toward the semiconductor chip can be gettered by the dielectric layer. Nevertheless, the dielectric layer is not sufficient to getter the copper diffusing from the through electrode.